Evidence for egg discrimination preceding failed rejection attempts in a small cuckoo host.

The article presents a study which examines egg discrimination following failed rejection attempts in a small cuckoo host. Conducted in northwestern Bulgaria, the study examined egg rejection behaviour in a host of common cuckoo Cuculus canorus and the eastern olivaceous warbler Hippolais pallida. Key findings indicate that olivaceous warblers failed to hold cuckoo eggs and can only remove them selectively by puncture ejection. Since the real cuckoo eggs were rejected at a very same rate suggests no appreciable discrimination in inferences from artificial eggs.